[This post is frequently updated]
Face ID will work for 1Password unlock on iPhone X if you enable it. See our blog post: Face it, The iPhone X Looks Amazing.
1Password 7 has been crafted to make the most of FaceID for the devices that support it. From our release notes:
The Latest and Greatest, At Home on the Latest and Greatest
When iPhone X was announced earlier this year we knew we wanted to be there, as always, on day one. Face ID is an absolute game-changer for productivity and efficiency. Simply tap to launch 1Password and Face ID instantly recognizes your face and unlocks. No waiting, no delays; just instant, secure access to your private information.
It is very early yet, and we will need to study Apple's documents and outside analysis to say anything with confidence. So everything I say here is going to be subject to change.
The secrets are stored the same way as with Touch ID. And so on that score there is no security difference between Face ID and Touch ID.
The attention grabbing concerns are
The dot projection and IR camera scheme looks like it will not be easy to spoof. But again, we will only know after people try. But it strikes me that this is going to be at least as hard to do as spoofing Touch ID.
The "attention" requirement should go a long way to mitigating the second threat.
Just as 1Password users currently have to make a choice about whether to enable or disable Touch ID unlock depending on their view of how particular threats apply to them, the same choice may need to be made for enabling Face ID unlock. With the very little we know now, we are leaving defaults the same. How this may change over time depends on what we learn, but release of 1Password for iOS 11 treats it the same way we have been treating Touch ID.